This invention relates to window assemblies for use in motor vehicles and the like, and relates more particularly to the protection of window panes in such vehicles against graffiti and other vandalism by transparent sheets serving as window liners to cover the windows in use and to be removable and replaceable when defaced.
Such window liners are specially designed for use on the insides of windows of public transportation vehicles such as busses and trains, where passengers sometimes scratch, paint or otherwise vandalize and deface the windows while riding in the vehicle. When windows are covered by protective liners, substantial savings are realized by replacing the liners, when necessary, to renew the windows at costs that are much less than the costs of removing and replacing, or even cleaning, the window panes themselves. It is important that the liners be mounted in a manner such that they are not easily removed by passengers but are relatively easy for service personnel to change with proper tools.
An example of a prior liner for these purposes is shown in U.S. Pat. No. 5,242,207, wherein a protective acrylic sheet is held removably in place over the interior of a window by a U-shaped frame or bracket that is attached to the permanent window frame along three sides of the window. This permits insertion of a liner sheet through the open side of the bracket into overlying relation with the window pane, and a fourth frame piece or bracket then is fixed in place over the open side with tamper-resistant screws which prevent removal of the liner by passengers in the vehicle. The brackets cover the peripheral edges of the liner to make access to the edges very difficult, except with special tools used by service personnel. With such tools, however, the protective liners may be replaced when needed at costs much lower than the costs of replacing window panes, and without necessity of removing the panes during the process.
The present invention resides in a novel window assembly for protecting the window pane from vandalism, wherein the window liner is held in place by liner-retaining strips that are removably installed in mounting grooves along the inner side of the window frame along the edges of the pane and have liner-retaining portions disposed outside the grooves to overlie the adjacent edge portions of the liner sheet. The strips are positioned along the frame and have anchor portions that are seated in the grooves after the liner sheet is in place, being locked in place with sufficient force to prevent easy removal by an occupant of the vehicle. Also, the strips are shaped and positioned to make gripping of the installed strips difficult for such occupants.
For these purposes, the liner-retaining strip of the invention has an external portion that forms a molding for overlying the edge portion of the liner sheet, preferably with the appearance of a common xe2x80x9cquarter roundxe2x80x9d molding, and a deformable xe2x80x9canchorxe2x80x9d portion that is pressed into and releasably secured in the mounting groove. The groove is formed with a restricted open side bordered by a detent rib having a locking shoulder, and the anchor portion is formed as an enlarged, deformable anchor and is joined to the external portion by a locking joint that interlocks with the locking shoulder of the groove. To maintain secure pressure of the external molding portion with the liner sheet, the strip is installed with the locking joint pre-stressed to press the molding portion against the liner sheet. It is preferred that the molding portion be long enough to engage the window pane if, for any reason, a liner sheet is not in place over the window. Several different configurations of liner strips are possible, the presently preferred strip being generally xe2x80x9cCxe2x80x9d shaped in transverse cross-section when relaxed, with a locking groove on its concave side to interfit with the locking shoulder in the groove in the frame. The preferred materials for the liner-retaining strips are resiliently flexible plastic, such as soft vinyl.
In accordance with another aspect of the invention, the frame mounting grooves are formed in elongated window-retaining strips that extend along the side portions of the window pane, close to the positions of the edges of the liner sheet, and are made easily installable and removable in a novel manner for ease of reglazing the window in the field. For this purpose, the window-retaining bars are positioned against the inner side edge portions of the window pane with the liner-retaining grooves in the exposed sides of the bars that face toward the glazed area of the window so as to extend along the margins of the exposed glass, and are secured to the frame of the window assembly by interlocking tongue-and-groove connectors that can be press-fitted together and are disengageable by skilled service personnel through a special, tilting manipulation.
The preferred embodiment of the interlocking tongue-and-groove joint is a locking groove in the window frame behind the window-retainer bar having a restricted open side bordered by a detent rib having a locking shoulder, similar to the locking shoulders for the liner-retaining strips, and an enlarged, deformable anchor portion forming an interlocking tongue. For considerably greater holding strength than is provided by the anchors on the liner , however, these anchor portions are resiliently flexible xe2x80x9cpositive lockingxe2x80x9d elements in the form of J-shaped, hard plastic tongues, such as rigid PVC or neoprene, that can be pressed into the grooves and then snap-lock into engagement with the locking shoulders. Removal requires special bodily tilting of the bars to disengage the tongues from the shoulders for removal of the bars during reglazing.
An alternative embodiment of the invention combines the resiliently flexible liner-retaining strips with the window-retaining bars in one elongated, integrally formed strip assembly capable of being installed in locking grooves formed directly in the window frame, so that the liner-retaining strips are readied for engagement with a window liner as an incident to the installation of the window-retaining in the window frame against a window pane. This alternative embodiment includes a locking strip for installation in the liner-retaining strips after a window liner is in place, and operable to hold the liner-retaining strip tightly against the window liner in service use.
Various other aspects and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.